Variable feed for drilling apparatus



Aug. 2, 1949. R. A. M CALLUM 2,477,701

VARIABLE FEED FOR DRILLING AEPARATUS Filed March 25, 1944 Patented Aug2, 1949 UNlTE'DfSTATESJ P TENT orFicE 1 it Q VARI BLE FEED Fzfifime I JRobert A. McCallum, Michigan City, ma, assignor to Joy ManufacturingCompany, a corporation of Pennsylvania Application March 25, 1944,Serial No. 528,101

18 Claims. '(cl. Ii-424.8)

My invention relates to drilling apparatus, and more particularly tofeeding means for such apparatus.

It is customary to provide for a drilling apparatus a feeding meansincluding intermeshing feed screw and nut elements rotatable relative toeach other to effect feed. These elements are usually mounted to rotateon flxed axes, and means are provided for rotating one or both at suchspeeds as to produce the relative rotation necessary to effect thedesired rate of feed.

If, .as contemplated by my invention, both of the elements are mountedfor rotation and are "adjustable to rotate on a common axis or on spacedparallel axes, it will be seen that, where one is caused to rotate byits threaded engagement with the other, there will be a difierence inthe rates of rotation varying directly with the spacing of the axes.When the elements rotate on a common axis their rates of rotation willbe the same, but, when one of the elements is moved transversely fromthe position in which the elements are concentric, the pitch diametersof the two elements are different and the rates of rotation vary by acorresponding amount. By providing the threads of the elements withinclined engaging surfaces, a pressure tending to move the elements intotheir coaxial positions will be obtained, this pressure varying directlywith the feeding pressure. If yielding means are provided for moving theelements out of their coaxial posi tions to effect feeding, it will beseen that the elements will be forced against the yielding means towardtheir coaxial positions when the feeding pressure reaches apredetermined value.

An object of my invention is to provide an improved drilling apparatus.Another object of my invention is to provide a drilling apparatus havingimproved feeding means. Still another object of my invention is toprovide an improved feeding means having feeding elements threadedlyengaging each other and movable relative to each other for varying therate of feed. Yet another object of my invention is to provide in animproved feeding means for a drilling apparatus, inter-meshing feedscrew and nut elements adjustable to rotate on a common axis or onspaced parallel axes while maintaining threaded engagement. Anotherobject of my invention is to provide an improved feeding means havingfeed screw and nut elements adjustable transversely relative to eachother for varying the rate of feed, and having yielding means forregulating the transverse adjustment of the elements. Still animprovedfeeding means operative automatically to limit the feeding pressure.Other objects of my invention will hereinafter more fully appear. In theaccompanying drawing, in which there is shown one illustrativeembodiment which my invention may assume in practice:

Fig. 1 is a longitudinal sectional view through a portion of a drillingapparatus having my improved feeding means.

Fig. 2 is an enlarged fragmentary sectional view showing my improvedfeeding means, and taken on the plane of Fig. 1.

Fig. 3 is a fragmentary sectional view similar to Fig. 2 but showingparts of the feeding means in difl'erent positions.

Fig. 4 is across sectional view taken on the planes of the line 4-4 ofFig. 3.

In the illustrative embodiment of my invention there is shown in Fig. 1a portion of a drilling apparatus, generally designated I, the drillingapparatus being herein of the bit rotating type and comprising anelongated screwlike member 2 adapted to effect rotation and feeding of abit, not shown. It will be understood that the member 2 may as well actmerely as a feed screw for feeding a drill mechanism or some othermechanism relative to its work. The feed screw 2 extends through asleeve-shaped member 3 which is rotatably supported at its ends bybearings 5 and 6 mounted within a casing 8. Attached in any suitablemanner to the ends of the casing are caps l and II having openings l2and I3 through which the feed screw extends. Formed in the feed screwalong its length are grooves ll which receive keys l fixed to thesleeve-shaped member 3 so that the feed screw and the member 3 arecaused to rotate together but are permitted to move longitudinallyrelative to each other. supported by the sleeve member 3 at pointsspaced along its length are bearings It on which beveled gears l1 and I8 are journaled. Formed integral with the gears I1 and I8, respectively,at their adjacent sides are clutch teeth and 2|, and a clutch member 23is slidably mounted on the sleeve member 3 and is provided at its endswith teeth 25 .adapted to intermesh with the teeth.

20 or 2!. The sleeve member 3 and the clutch member 23 are connected, asby a key 26, for rotation together. Extending through an opening in theside of the casing 8 is a power shaft 28 carrying a beveled gear 29which meshes with the gears l1 and I8. The power shaft is rotatablysupported by a bearing 30 mounted in a frame 3| which is attached, as byT-bolts 32.

other object of my invention is to provide an to a collar 33 fixed inany suitable manner to the side of the casing 8. It will be seen that arotation of the gear 28 will cause the gears l1 and II to rotate inopposite directions, and that the sleeve member 8 may be caused torotate in either direction by sliding the clutch member 23 in onedirection or the other into engagement with the teeth 28 or 2 i. Theclutch member may be moved manually to its different positions by anysuitable actuating member, not shown, extending into an annular groove38 formed in the clutch member. The power shaft 28 may be the shaft ofan electric motor attached to the frame II. or may be connected througha suitable transmission mechanism to any power unit.

Operatively connected to the feed screw are feeding means, generallydesignated 31, for effecting longitudinal movement of the feed screw.This feeding means includes a feed nut 88 having internal threads 38intermeshing with threads 48 formed on the outer surface of the feedscrew. The threads 38 and 48, respectively, are provided with inclinedside surfaces 4| and 42 which engage each other during the feeding ofthe bit, and the threads are so formed that the feed nut and the feedscrew may be moved transversely relative to each other out of coaxialrelationship, as shown in Fig. 3. The feed nut 38 is rotatably supportedby a ball bearing 44 which has its outer ring clamped between plungers48 and 48 fitting within diametrically opposite openings 41 and 48 inthe side walls of the casing 8. The point of support of the feed nut bythe bearing 44 is such that the forces on the feed nut are in balance,and the nut is held at all times with its axis parallel to the axis ofthe feed screw. A plate 49 is bolted over the opening 41, and anadjusting screw 80 is threaded through an opening in the plate intoengagement with a movable abutment 8| between which and the plunger 48 aspring 82 is arranged. The opening 48 is covered by a plate 84. and aspring 88 acting between this plate and the plunger 48 holds the latteragainst the outer ring of the bearing 44. Attached to the upper end ofthe feed nut is an annular member 81 for clamping the inner ring of thebearing 44 against a shoulder 58 formed on the feed nut. Below the feetnut is a sleeve-shaped member 88 rotatably supported by a ball bearing8| in a position to be engaged at its upper end by the lower end of thefeed nut. The inner ring of the bearing 8| fits between a locking ring88 and a shoulder 84v on the sleeve member 88 so as to preventlongitudinal movement of the latter, and the outer ring of the bearingis held in the casing 8 by the cap I I and a locking ring 88.Surrounding the feed nut is a sleeve member 61 yieldably held inengagement with the outer ring of the bearing 44 by a spring 88 actingbetween the lower end of the sleeve member and the outer ring of the.bearing 8i. Supported within the lower end of the sleeve member 3 andthe inner ring of the bearing 8 is a thrust collar 18 adapted to beengaged by the upper end of the feed nut for limiting the upwardmovement of the latter. The sprin 88 and the sleeve member 81 operate tohold the bearing 44 so that the upper end of the feed nut engagesinitially the lower end of the thrust collar 78. The feeding pressuresset up during normal operation of the machine act to hold the feed nutmore firmly in engagement with the thrust collar. The adjacent ends ofthe feed nut and the thrust collar are provided. respectively, withinclined surfaces H and 12 which act in the same manner as the surfaceson the threads 89 and 40 to produce a feeding pressure when the feed nutis moved out of coaxial relationship with the feed screw. The thrustcollar and the sleeve member are spaced apart a-sufflcient distance topermit a slight longitudinal move ent of the feed nut. Projectingthrough an 0 ng in the casing 8 is a plunger 13 adapted to have itsinner end moved into a recess I4 in the feed nut for holding the latteragainst rotation and eflecting rapid feed of the feed screw. A spring 18acting between the casing 8 and the plunger 13 urges the latteroutwardly toward its released position.

The operation of the mechanism described is as follows: The power shaft28 is caused to rotate and drive the gears I1 and it through the gear28, and the clutch member 28 is moved into engagement with the clutchteeth 28 or 2| to effect rotation of the feed screw 2 in the desireddirection. The feed screw may be fed rapidly as it rotates by forcingthe plunger 18 into the recess 14 in the feed nut so that the latter isheld stationary. When the plunger 13 is released from the recess 14 andthe feed nut is in a position coaxial with the feed screw, the feed nutand the feed screw will rotate at the same speed and no feeding of thescrew will take place. If the adjusting screw 881s screwed in tocompress the spring 82 and increase the force of the plunger 48 againstthe outer ring of the bearing 44, the bearing and the feed nut will bemoved trans- .versely against the action of the plunger 46, and,

since the thread surfaces 4| and 42 are inclined, the threads willengage each other theoretically in line contact at the side where thethreads of the feed nut are nearer to the axis of the feed screw. Itwill be seen that the threads 39 and 40 will then roll on unequal pitchdiameters, the feed nut rotating slower than the feed screw and causinga feeding of the latter. The feeding pressure on the feed screw producesa force, by reason of the inclined thread surfaces, which tends to movethe feed nut against the action of the plunger 48 toward a position inwhich it is coxial with the feed screw. Since the screw 80 may beadjusted to vary the yielding pressure on the plunger 48, an automaticcontrol is obtained for limiting the feeding pressure to any desiredvalue.

As a result of my invention there is provided animproved feeding meansadapted for use with a drilling apparatus. It will be noted that a rapidfeed or a variable slow feed may be obtained, the feeding means beingoperative automatically to vary the slow feed so that the feedingpressure does not exceed a predetermined value. It will be noted furtherthat the slow and rapid feeding of the screw may be obtained in eitherdirection.

While there is in this application specifically described one form whichthe invention may assumein practice, it will be understood that thisform of the same is shown for purposes of illustration and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new arid desire to secure by Letters Patent is:

1. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements. the supporting means forone of said elements permitting movement of said element transverselyrelative to the other 0f said elements, means for moving said lastmentioned element transversely relative to the other of said elements,and means for rotating one of said elemen 2. In a feeding device, incombination. a feed screw element, a feed nut element threadedlyengaging said feed screw element, means for rotatably supporting saidfeed screw and nut elements,

the supporting means for one of said elements ineluding yielding meanspermitting movement of I said element transversely relative to the otherof said elements, and means for rotating one of said elements.

3. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements, the supporting means forsaid feed nut element including yielding means permitting movement ofsaid element transversely relative to said feed screw element, and meansfor rotating said feed screw element.

4. In a feeding device. in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements,

the supporting means for one of said elements ineluding yielding meanspermitting movement of said element transversely relative to the otherof said elements, means for adjusting said yieldable supporting means sothat the element yieldably supported thereby is urged toward a positionin which its axis is in spaced parallel relation with the axis of theother of said elements, and means for rotating one of said elements.

5. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements, the supporting means forsaid feed nut element including yielding means permitting movement ofsaid element transversely relative to said feed screw element, means foradjusting said yieldable supporting means so that the feed nut elementis urged toward a position in which its axis is in spaced parallelrelation with the axis of said feed screw element, and means forrotating said feed screw element.

6. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements, the supporting means forsaid feed nut element including yielding means permitting movement ofsaid element transversely relative to said feed screw element, manuallycontrolled means operable to effect a holding of said feed nut elementagainst rotation, and means for rotating said feed screw element.

7. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut element, the supporting means for oneof said elements including yielding means permitting movement of saidelement transversely relative to the other of said elements, manuallycontrolled means operable to eiiect a holding of one of said elementsagainst rotation, and means for rotating the other of said elements.

8. In a feeding device, in combination, a feed screw element, a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements, the supporting means forone of said elements permitting movement of said element betweenpositions in which its axis coincides with and is in spaced parallelrelation with, the axis of the other of said elements, means for moving6 said movable element between said positions, and means for rotatingone of said elements.

9. In a feeding device, in combination, a feed screw element. a feed nutelement threadedly engaging said feed screw element, means for rotatablysupporting said feed screw and nut elements, the supporting means forone of said elements including yielding means adapted to support saidelement so that it is movable between positions in which its axiscoincides with and is in spaced parallel relation with, the axis of theother of said elements, and means for rotating one of said elements.

10. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, means forrotatably supporting said feed screw and nut elements, the supportingmeans for said feed nut element including yielding means adapted tosupport said element so that it is'movable between positions in whichits axis coincides with andis in spaced parallel relation with, the axisof said feed screw element, and means for rotating said feed screwelement.

11. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, means forrotatably supporting said feed screw and nut elements, the supportingmeans for one of said elements including yielding means adapted tosupport said element so that it is movable between position in which itsaxis coincides with and is in spaced parallel relation with, the axis ofthe other of said elements, means for adjusting said yieldablesupporting means so that the element yieldably supported thereby isurged toward a position in which its axis is in spaced parallel relationwith the axis of the other of said elements, and means for rotating oneof said elements. Y

12. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, means forrotatably supporting said feed screw and nut elements, the supportingmeans for said feed nut element including yielding means adapted tosupport said element so that is is movable between positions in whichits axis coincides with and is in spaced parallel relation with, theaxis of said feed screw element, means for adjusting said yieldablesupporting means so that the feed nut element is urged toward a positionin which its axis is in spaced parallel relation with the axis of saidfeed screw element, and means for rotating said feed screw element.

13. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, means forrotatably supporting said feed screw and nut element, the supportingmeans for said feed nut element including yielding means adaptedtosupport said element so that it is movable between positions in whichits axis coincides with and is in spaced parallel relation with, theaxis of said feed screw element, manually controlled means operable toeffect a holding of said feed nut element against rotation, and meansfor rotating said feed screw element.

14. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, means forrotatably supporting said feed screw and nut elements, the supportingmeans for one of said elements including yielding .means adapted tosupport said element so that it is movable be- 7 tween positions inwhich its axis coincides with and is in spaced parallel relation'with,the axis of the other of said elements, manually con- .trolled meansoperable to efiect a holding of one of said elements against rotation,and means forrotating the other of said elements:

15. In a feedingdevice, in combination, a feed screw element, a' feednut element threadedly engaging said feed screw element, the threads ofsaid feed screw and nut elements having radially inclined engagingsurfaces arranged to permit longitudinal and transverse movements ofsaid elements relative to each other, means for rotatably supportingsaid feed screw. and nut elements, the supporting means for one of saidelements including yielding,means adapted to support said element sothat it is movable bea tween positions in which its axis coincides withand is in spaced parallel relation with, the axis of the other of saidelements, and means for rotating one of said elements.

16. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, the threads ofsaid feed screw and nut elements having radially inclined engagingsurfaces arranged to permit longitudinal and transverse movements ofsaid elements relativeto each other, means for rotatably supporting saidfeed screw and nut elements, the supporting means for said feed nutelement including yielding means adapted to support said element so thatit is movable between positions in which its axis coincides with and isin spaced parallel relation with, the axis of said feed screw element,and means for rotating said teed screw element.

17. In a feeding device, inv combination. a feed screw element, a feednut element threadedly engaging said feed screw element, the threads ofsaid feed screw and nut elements having radially inclined engagingsurfaces arranged to permit longitudinal and transverse movements ofsaid elements relative to each other, means for rotatably supportingsaid feed screwand nut elements including yielding means adapted to.

support said element so that it is movable between positions in whichits axis coincides with and is in spaced parallel relation with, theaxis of the other of said element, means for adjusting said yieldablesupporting means so that the element yieidably supported thereby isurged toward a position in which its axis is in spaced parallel relationwith the axis of the other of said elements, and means for rotating oneof said elements.

18. In a feeding device, in combination, a feed screw element, a feednut element threadedly engaging said feed screw element, the threads ofsaid feed screw and nut elements having radially inclined engagingsurfaces arranged to permit longitudinal and transverse movements ofsaid elements relative to each other, means for rotatably supportingsaid feed screw and nut elements, the supporting means for said feed nutelement including yielding means adapted to support said element so thatit is movable between positions in which its axis coincides with and isin spaced parallel relation with, the axis of said feed screw element,means for adjusting said yieldable supporting means so that the feed nutelement is urged toward a position in which its axis is in spacedparallel relation with the axis of said feed screw element, and meansfor rotating said feed screw element.

, ROBERT A. McCALLUM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 788,716 Hammond et al. May 2,1905 924,122 Williams June 8, 1909 949,163 Stapley Feb. 15, 19101,589,307 Svebilius June 15, 1926

